1. Field of the Invention
The present invention relates to the repair of bone fractures and the correction of bone defects using external fixation frames wherein an adjustment of one frame part with respect to another through translation or rotation is swiftly accomplished using a fine adjustment translator that can be interfaced with the external fixation frame parts.
2. General Background
The repair of traumatized bone can be accomplished by the use of an external fixator device which includes a number of curved rings or curved half rings that are attached and spaced apart but structurally connected using a plurality of tie rods. These tie rods are simply inserted through one of several holes formed in each of the selected half rings or rings at a desired circumferential position and affixed thereto by bolting.
Several rings and several tie rods can be used by the surgeon in order to create an overall frame about the patient's arm or leg. Transversely extending pins or wires attach to these rings and then extend transversely from the rings into the bones, so that the frame and transverse pins support and/or load the bone tissue in a desired manner. This external fixation system is generally referred to in the art as the "Ilizarov technique".
The "Ilizarov" technique can be used for the purpose of external fixation of heavily damaged or heavily traumatized bone. The "Ilizarov" technique can also be used for lengthening various congenital and acquired shortenings and other defects of skeletal segments wherein the rings and tie rods form part of a compression-distraction apparatus.
The "Ilizarov" technique is described generally in the Oct. 8, 1989 issue of Parade Magazine in an article entitled "Stretching The Body's Power To Grow", and in U.S. Pat. No. 4,615,338, issued to Gavril A. Ilizarov et al. The '338 patent, entitled "Automatic Compression-Distraction Apparatus" , is directed to an improved compression distraction apparatus. The '338 Ilizarov patent references earlier prior art publications of the same inventor, including USSR Inventor Certificate No. 848,011,cl.A 61 B 17/18, also published in the Bulletin of Inventions No. 27,1981. A second prior art disclosure relating to a drive of a compression distraction apparatus appears in USSR Inventor Certificate No. 865,284,cl.A 61 B 17/18, published in the Bulletin of Inventions No. 35,1981. These prior Ilizarov publications all relate generally to the Ilizarov external fixation system which uses metal rings, threaded rods, threaded fasteners, and other metallic components in the fixation of fractures and the correction of congenital bone deformities.
During the course of treatment of patients undergoing the "Ilizarov" technique, it is at times necessary to translate or rotate one segment of the "Ilizarov" apparatus with respect to the other. Previously, this has been accomplished with standard "Ilizarov" components arranged in such a manner to permit the necessary translation or rotation. A problem with this approach of achieving translation or rotation is that it is exceptionally time consuming for the surgeon to assemble the appropriate construct on the "Ilizarov" frame. In addition, depending upon the unique demands of the particular patient, these constructs can be rather complex and for the new "Ilizarov" surgeon extremely difficult to visualize and assemble.
The Mears Pat. No. 4,620,533 relates to an apparatus for externally fixing bone fractures with clamps having universal ball joints to pins and a rigid bar. Other patents include the Kalnberz Pat. No. 4,033,340 entitled "Surgical Compression Distraction Instrumentation" and 3,977,397 entitled "Surgical Compression Distraction Instrumentation". The '340 patent deals with translation or rotation of an "Ilizarov " type external fixator. In the Kalnberz '340 patent there is provided attachment of an exterior ring to the circular fixator and manipulation of the circular fixator with respect to that external ring is provided. This apparatus thus attempts to provide rotation only. In the Kalnberz '340 patent the surgical instrument is adapted to adjust the position of bone fragments of a limb. It has an outer ring with longitudinal connecting members and a smaller ring carrying clamps for needles fixed within a larger ring. A system of threaded studs enables the inner ring to move in any direction and turn within the outer ring. The inner ring can also be positioned in a plane turned by an angle with respect to the plane of the outer ring.
In the Kalnberz Pat. No. 3,977,397, an instrument for treating injuries and diseases of bones and joints incorporates rings with needles passed through bone fragments. Adjacent rings are interconnected by longitudinal permanently sprung members, namely helical springs and/or rods connected with the rings by means of nuts. To stabilize the structure, strengthening rings composed of separate arches and carrying locking means for additional needles may be inserted into the instrument. The '397 patent discusses an early Ilizarov inventor certificate number 98,471 granted June 9, 1952. Another inventor certificate, USSR inventor certificate number 367858 is discussed in the '340 Kalnberz patent naming inventors Sinilo, Sarancha, and Nadein. The instrument referred to in that inventor certificate comprises a slotted support arch, a distal arch, and a split ring as well as coupling screws, needles and fastening members, the ring being connected with the support arch by means of threaded link studs arranged radially and tangentially with resect to the ring.